Elements, Compounds and Mixtures Flashcards
Are covalent bonds really strong or really weak?
Really strong
Are ionic bonds really strong or really weak?
Really strong
Can graphene conduct electricity?
yes
Can you see nanoparticles with a light microscope?
No, they are too small
Do metals have a high melting point?
Yes
Do simple covalent substances need a high or low temperature to melt/boil?
Low temperature
Does graphite have a high or low melting point?
High due to strong covalent bonds
Give 2 properties of ionic compounds
High melting and Boiling point
Conduct electricity when melted or dissolved
Give 3 examples of Giant Covalent Structures.
Silicon Dioxide
Diamond
Graphite
Give 3 types of substances covalent bonding can make.
Simple molecular substances
Polymers
Giant Covalent Structures
How are anions formed?
When non-metals react with a metal to achieve a full outer shell, giving them a negative charge.
How are the atoms arranged in graphite?
They are arranged in hexagonal flat sheets, which form layers over one another
How can you model the ions in an ionic compound?
with the dot and cross diagram.
How do covalent bonds work?
Electrons are shared between atoms, so each gains electrons.
How do ionic compounds form?
when a metal reacts with a non-metal, electrons are transferred from the outer shell of the metal to the non-metal. This makes the non-metal an anion and the metal a cation.
How do you conduct crystallisation?
1) place solution into evaporation dish
2) heat with water bath
3) once you start seeing some crystals forming after some of the solvent has evaporated, stop heating and leave to cool
4) when it cools more crystals should form
5) then conduct filteration to filter out the crystals
How do you work out moles?
mass/ mr
How does ionic bonding work?
Electrons are transferred from one atom to another, creating to ions of opposite charges. They attract due to their opposite charges and form an ionic bond.
How does metallic bonding work?
The atoms give up the electrons in their outermost shell and become cations. The electrostatic forces between the neg. electrons and pos. ions, hold everything together.
How does paper chromatography separate substances?
a solution with multiples substances is put onto the baseline and the paper is put in a solvent which is under the baseline. As the solvent travels up, the solution dissolves in the solvent and travels up. The more soluble substances in the solution travel further up the mobile phase than the less soluble ones
How does simple distillation work?
The solution is heated, and the liquid evaporates. The evaporated liquid passes through a tube with a water jacket around it. The water jacket has continuous cold water coming in from the bottom and exiting from the top. The water jacket condenses the evaporated liquid and it falls into a beaker
How does the apparatus look for simple distillation?
a circular flask with a cork with a temperature which a tube extending from the neck. A water jacket around the extended tube (condenser).
How is a cation formed?
when metals react, they lose their outer shell electrons, giving them a positive charge
How many carbon atoms are each carbon atom bonded to in graphite?
3 others
How many carbon atoms does buckminsterfullerene have?
60
How many electrons can the first shell hold?
2
How many electrons can the third shell hold?
8
How many other carbon atoms is one carbon atom bonded to in diamond?
4 other carbon atoms
What 2 elements is steel usually made from?
Mostly iron, and some carbon
What are 2 alloptropes of carbon?
Diamond and Grpahite
What are 2 properties of giant covalent structures?
Very strong
High melting/boiling point
What are 2 features of the fractionating column?
it is full of glass rods
cooler at the top than at the bottom
What are 2 ways to separate a solution?
evaporation and crystallisation
What are 4 examples of formulations?
fuels, cleaning agents, paint, medicines, alloys, fertilisers
What are formulations?
mixtures that have been prepared using a specific formula
What are fullerenes?
Graphene bent into tubes or spheres
What are group 0 elements called?
Noble Gases
What are group 7 elements called?
Halogens
What are polymers?
Long chains of repeating monomers
What are the 2 types of distillation?
simple and fractional
What are the 3 types of bonding?
Metallic, Ionic, Covalent
What can scientists use sphereical fullerenes for?
They can form shperes around other molecules like drugs to act as a cage to deliver the drugs to a specific part of the body
What can the tube fullerenes be used for?
They can be used to strengthen other materials like tennis racquets as they have are very long and thin, which allows them to add a lot of strength with little weight
What do atoms need in order to be stable?
A full outer shell
What does filtration separate?
an insoluble solid from a liquid
What does inert mean?
Non-reactive
What does the atomic number show?
Amount of protons
What does the mass number show?
Amount of neutrons + protons
What happens to the melting and boiling points when there are impurities in your sample?
The melting point decreases, and the boiling point increases
What is a giant ionic lattice?
ionic compounds in their solid state, which contain regularly arranged anions and cations
What is a key feature of nanoparticles?
They have a very large surface area to volume ratio
What is a pure substance?
A substance that only contains one type of element or compound
What is a pro and a con of evaporation as a separation technique?
pro: quick and easy to evaporate solvent
con: some solids decompose when heated
What is a single layer of graphite called?
Graphene
What is an allotrope?
Different structural forms of the same elemnt in the same physical state
What is a stationary phase in chromatography?
a substance molecules cant move through
What is an alloy?
A mixture of a metal and at least one other element
What is another name for group 1 elements?
Alkali Metals
What is simple distillation used for?
to separate out a liquid from a solution
What is the difference between a molecule and a compound?
a molecule is 2 or more atoms held together by chemical bonds, but a compound is 2 or more different elements held together by chemical bonds
What is the difference between the melting and boiling points of pure and impure substances?
impure substances boil over a range of temperatures, whereas pure substances boil at a certain temperature
What is the formula of buckminsterfullerene?
C60
What is the mobile phase in chromatography?
The substance that the molecules can move in
What is the Rf value?
distance travelled by the substance / distance travelled by the solvent
What is the size of a nanoparticle?
1nm - 100nm
What is the symbol and ionic charge of Nitrate?
NO3 1-
What is the symbol and ionic charge of Sulphate?
SO4 2-
what is thermal decomposition?
When solids break down when heated
What kind of technology are fullerenes used in?
Nanotechnology
What type of atoms do covalent compounds contain?
multiple non-metal atoms
What type of atoms do ionic compounds contain?
at least on metal and one non-metal.
What type of atoms do metallic compounds contain?
multiple metal atoms
What type of structures are diamond and graphite?
Giant Covalent Structures
What was one of the first fullerenes made?
Buckminsterfullerene
What would be the mobile phase in paper chromatography?
the solvent used
When is fractional distillation used?
when the misture has multiple liquids with similar boiling points
Which covalent structure conducts electricity?
graphite
Which nanoparticles are known to have anti-bacterial properties?
nanoparticles containing silver
Why are alloys less malleable and stronger than pure metals?
The regular structure is disturbed by the different sized atoms of different elements, so the layers can’t slide over one another as easily
Why are metals malleable?
They have a regular structure, so the layers can slides over one another.
Why can fullerenes be used as industrial catalysts?
They have a high surface area : volume ratio
Why can graphite conduct heat and electricity?
The carbon atoms are only bonded to 3 other carbon atoms in graphite. This means they each have one spare electron which becomes de-localised. Becuase of this de-localised electron, electricity and heat can be conducted
Why can ionic compounds only conduct electricity when molten or dissolved?
The ions become free to move around so they can carry the charge
Why do atoms want to react?
They don’t have a full outer shell, so by reacting, they will gain or lose enough electrons to get a full outer shell
Why do covalent structure not conduct electricity?
There are no ions present so they cannot conduct electricity
Why do metals conduct electricity and heat?
they have delocalised electrons which can carry the charge
Why do simple covalent substances only need a low temp. to melt/boil?
covalent bonds are strong but to melt or boil simple covalent substances you only need to break the weak intermolecular forces between each molecule.
why does diamond not conduct electricity?
The atoms are covalently bonded so there are no free ions to carry the charge
Why is graphite soft?
The the layers of carbon atoms are held together weakly as there are no covalent bonds between them. This means that they can slide over one another.
Why is the fractionating column full of little glass rods?
they provide a high surface area
